Apparatus for low pressure chemical vapor deposition

ABSTRACT

An improved apparatus for a lower pressure chemical vapor deposition capable of achieving various kinds of thin films having a uniform thickness, preventing parts breakage, achieving automation of the system, and combining the use of a low pressure chemical vapor deposition apparatus and a plasma low pressure chemical vapor deposition apparatus, which includes a deposition base; a reactor disposed on the deposition base and having a reaction region formed therein; a substrate lifted and lowered in the reactor and on which a wafer is placed; a chemical source gas introducer for introducing a chemical source gas into the reactor; a substrate heating member disposed in the substrate for heating the wafer; and a reactor heating member for heating the reactor.

CROSS REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.08/571,404 filed on Dec. 13, 1995, now U.S. Pat. No. 5,928,427.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an apparatus for a low pressurechemical vapor deposition, and particularly to an improved apparatus fora low pressure chemical vapor deposition capable of achieving afabrication of various kinds of thin films having a uniform thickness,preventing breakages of the parts, achieving automation of the system,and combining the use of a low pressure chemical vapor depositionapparatus and a plasma low pressure chemical vapor deposition apparatus.

2. Description of the Conventional Art

As well known to those skilled in the art, the low pressure chemicalvapor deposition (hereinafter called an "LPCVD") technique has beenwidely used so as to deposit nitride layers, oxide layers, siliconlayers, and the like on a wafer having insulating, dielectric orconductive characteristics.

The deposition apparatus adopted in the LPCVD is directed to depositinga compound-made thin film on a wafer by reacting a chemical source gasin a reactor under a low pressure. This apparatus includes a singlewafer input low pressure chemical vapor deposition device for depositingwhile loading wafer one by one and a vertical type low pressure chemicalvapor deposition device for depositing in a state that a plurality ofwafers are loaded. In addition, the single wafer input low pressurechemical vapor deposition apparatus has advantages in that it is easy tomake the system automated and does not require wide foot point.

Hereinafter, only the single wafer input low pressure chemical vapordeposition apparatus of the conventional low pressure chemical vapordeposition apparatuses will now be explained.

FIG. 1 shows a conventional single wafer input low pressure chemicalvapor deposition apparatus, which includes a deposition base 11 having awafer inlet 11a and an outlet 11b for discharging reaction substancesand opened/closed by an opening/closing plate 11c, a reactor 12 disposedabove the deposition base 11 for forming a reaction space "S", achemical source gas introducer 13 disposed on the upper portion of thereactor 12, and a substrate 14 which is lifted/lowered within thereaction space "S" by a lifting/lowering ram 15 passing through theopening/closing plate 11c.

The above-mentioned conventional single wafer input low pressurechemical vapor deposition apparatus is directed to placing a wafer "W"on the substrate 14 by introducing the wafer "W" through the wafer inlet11a in a state that the substrate 14 is lowered down to aloading/unloading position lower than the wafer inlet 11a, and liftingthe substrate 14 using the lifting/lowering ram 15, driving a substrateheating member 16 disposed at the substrate 14, and introducing chemicalsource gas into the reactor 12 through a chemical source gas introducer13, whereby the chemical source gas is deposited on the wafer "W" so asto form a compound thin film.

However, the conventional single wafer input low pressure chemical vapordeposition apparatus has disadvantages in that when heat is applied tothe substrate 14 having a wafer "W", since the heat is not applied tothe reactor 12 and its periphery, the thermal effect is deteriorated.Due to the above-mentioned thermal effect, the pin hole is caused at thethin film, and the step coverage is decreased.

In addition, because the conventional single wafer input low pressurechemical vapor deposition apparatus provides the chemical source gasintroducer 13, connected to a lower portion of the introduction tube 13apassing through the upper surface of the reactor 12, and a shower head13b having a plurality of shower apertures so as to simply ejectchemical source gas, so that a desired compound mixing cannot beachieved, whereby non-uniform layer can be deposited on the entire wafersurface.

Moreover, in order to overcome the above-mentioned problems, the plasmaenhanced low pressure chemical vapor deposition apparatus, which ischaracterized to reacting the chemical source gas by generating plasmaby connecting a plasma generator to the substrate and the electrode ofthe reactor, was introduced.

As shown in FIG. 2, the conventional plasma low pressure chemical vapordeposition apparatus includes a deposition base 21 having an inlet 21aformed at one side thereof and an outlet 21b formed at the other sidethereof, wherein the lower portion thereof is opened/closed by anopening/closing plate 21c, a reactor 22 disposed at an upper portion ofthe deposition base 21, a chemical source gas introducer 23 disposed atthe upper surface of the reactor 22, a substrate 24 on which a wafer"W", which can be lifted/lowered within the reactor 22 by alifting/lowering ram 25 through the opening/closing plate 21c, ismounted, a substrate heating member 26 disposed at the substrate 24, anda plasma generator 27 disposed at the reactor 22 and the substrate 24and connected to electrodes 27a and 27b.

The above-mentioned conventional plasma low pressure chemical vapordeposition apparatus is directed to depositing a compound thin film on awafer "W" by lowering the lifting/lowering ram 25 through theopening/closing plate 21c and the substrate 24 down to aloading/unloading position lower than the inlet 21a, by mounting thewafer "W" on the substrate 24 through the inlet 21a, and by generatingplasma in the reactor 22 by driving the plasma generator 27 connected tothe electrodes 27a and 27b mounted on an upper portion of the reactor 22and the substrate while introducing the chemical source gas into thereactor 22 through the chemical source gas introducer 23 and whileheating the substrate and the wafer "W" by driving the substrate heatingmember 26 after lifting the substrate 24 with the wafer "W" up to thedeposition position.

The above-mentioned plasma low pressure chemical vapor depositionapparatus has advantages in that it can minimize a characteristicvariation of a device due to a deposition temperature by maintaining theprocess temperature at a low temperature by ionizing the chemical sourcegas by generating plasma. However, it has disadvantages in that the heateffect is deteriorated because the chemical source gas is introducedinto a reaction space "S" in a state that the chemical source gas is notsubstantially heated since only the substrate 24, on which the wafer "W"is mounted, is heated, and its periphery is not substantially heated. Inaddition, pin hole can occur at the thin film due to the above-mentionedlower heat effect, and the step coverage is deteriorated.

Moreover, because the chemical source gas introducer 23 is simplyconnected to the introduction tube 23a passing through an upper portionof the reactor 22 and a lower portion of the introduction tube 23a andincludes a shower head 23b having a plurality of shower apertures, sothat substantial pre-heating and mixing of the introducing chemicalsource gas are not performed and the wafer "W" which is loaded on thesubstrate 24 cannot have substantial flooded by the chemical source gas,the uniformity level of the compound thin film is lowered.

In addition, since the wafer "W" mounted on the substrate is directlyexposed to the lower portion of the shower head, the wafer "W" is notsubstantially exposed with respect to the chemical source gas, so thatthe uniformity level of the thin film is lowered.

Moreover, since the waste gas in the chemical reaction is exhausted fromthe outlet, and the gas in the reactor cannot be exhausted at a desiredspeed, the remaining gas affects the quality of the thin film.

Referring to FIGS. 1 and 2, since the conventional low pressure chemicalvapor deposition apparatus and the conventional plasma low pressurechemical vapor deposition apparatus provide the substrates 14 and 24which are connected to an upper portion of the lifting/lowering rams 15and 25 and lifted/lowered within a range between the loading/unloadingposition and the deposition position, the desired preciseloading/unloading cannot be achieved, disadvantageously affectingautomation of the system.

In addition, referring to FIG. 4, the substrates 14 and 24 in theconventional low pressure chemical vapor deposition apparatus and theplasma low pressure chemical vapor deposition apparatus include thewafer placement sections 14b and 24b, on which the wafer "W" is mounted,being higher than the bodies 14a and 24a having the substrate heatingmember, and wafer supporting protrusions 14c and 24c provided at aperiphery of the wafer placement sections 14b and 24b, so that the wafer"W" is stably placed on the wafer placement sections 14b and 24b in thesupport protrusions 14c and 24c.

However, conventionally, the wafer "W" having a flat zone "F" iscircular and is mounted on the substrates 14 and 24 through the waferinlets 11a and 12a using a robot hand "R". Here, since the fork-shapedrobot hand "R" interferes with the wafer placement sections 14b and 24bduring a certain operation mode, part of the both inner sides of thewafer placements 14b and 24b are cut away to be straight line sections14d and 24d, so that the robot hand "R" freely operates between thestraight line sections 14d and 24d. In addition, the width between thestraight line sections 14d and 24d is smaller than the width between theinner sides of the fork of the robot arm "R".

In the above-mentioned construction, when lowering the robot hand "R"after moving the robot hand "R" to a position precisely mating with thewafer placement sections 14b and 24b, since the robot hand "A" islowered at the outer side of the straight line sections 14d and 24d ofthe wafer placement sections 14b and 24b, there is not any interferencebetween the robot hand "A" and the wafer placement sections 14b and 24b,and the wafer "W" is safely placed on the support protrusions 14c and24c formed at the rim of the wafer placement sections 14b and 24b. Whenunloading the wafer, the operation is executed in the reverse order ofthe above-mentioned order.

However, referring to FIG. 3, when the wafer "W" is placed on the waferplacement sections 14b and 24b, since the both sides of the wafer "W" donot come into precise contact with the wafer placement sections 14b and24b, that is, the wafer "W" slightly comes off from the straight linesections 14d and 24d of the wafer placement sections 14b and 24b, theheat of the substrate heating member in the substrate bodies 14aa and24a is not evenly transferred to the entire surface of the wafer "W",and a desired deposition cannot be executed with respect to the bothsides of the wafer "W", and the deposition with respect to the lowersurface of the wafer "W" is executed because the chemical source gas isintroduced over part of the lower surface of the wafer "W" in a statethat the both sides of the wafer "W" is slightly lifted.

In addition, referring FIGS. 4A and 4B, in order to resolve theabove-mentioned problems, wafer lifting/lowering pins 17 and 28(preferably three) which are lifted/lowered in the wafer placementsections 14b and 24b of the substrates 14 and 24 are provided. That is,as shown FIG. 4A, in a state that the wafer lifting/lowering pins 17 and28 are lifted, the wafer "W" is positioned on the robot hand "A", and asshown in FIG. 4B, the wafer "W" is stably placed on the wafer placementsections 14b and 24b by lowering the lifting/lowering pins 17 and 28unless the straight line sections of both sides of the wafer placementsections 14b and 24b formed on the substrate bodies 14a and 24a are notprovided.

However, in this case, a certain gap is formed between the substratebodies 14a and 24a and the wafer lifting/lowering pins 17 and 28 whenmounting the wafer lifting/lowering pins 17 and 28. The chemical sourcegas infiltrates through the gap causing particles. In addition, it isdifficult to precisely dispose the substrate heating member and theelectrodes in the substrate bodies 14a and 24a. Moreover, the gasinfiltrated into the gap affects the substrate heating member causingheat loss. In addition, since the wafer lifting/lowering pins 17 and 28are made of SUS or quartz, the wafer lifting/lowering pins 17 and 28 caneasily broken, and it is difficult to maintain them.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide anapparatus for a low pressure chemical vapor deposition, which overcomethe problems encountered in the conventional low pressure chemical vapordeposition apparatus.

It is another object of the present invention to provide an improvedapparatus for a lower pressure chemical vapor deposition capable ofachieving various kinds of thin films having a uniform thickness,preventing parts breakage, achieving automation of the system, andcombining the use of a low pressure chemical vapor deposition apparatusand a plasma low pressure chemical vapor deposition apparatus.

It is another object of the present invention to provide an improvedapparatus for a lower pressure chemical vapor deposition, which canincrease the quality of the compound thin film and is capable ofpreventing particle occurrence by increasing the heat efficiency and bypre-heating the reactor, its peripheral portion, and the wafer while thechemical source gas is introduced into the reactor using a substrateheating member.

It is another object of the present invention to provide an improvedapparatus for a lower pressure chemical vapor deposition, which iscapable of increasing the quality of a thin film deposition and ofpreventing the particle occupance by enhancing the heat efficiency sothat the chemical source gas passes through the gas pre-heating region,the gas mixing region and a reaction region while the chemical sourcegas is introduced into the reactor.

It is another object of the present invention to provide an improvedapparatus for a lower pressure chemical vapor deposition, which iscapable of achieving a uniform thin film so that the temperaturedistribution is evenly provided by allowing the heat generated by thereactor heating member to be transferred to the reaction region byproviding an indirect heat transfer member, at a periphery of thereactor, and a reactor, which are made of a material having an indirectheat transfer property.

It is another object of the present invention to provide an improvedapparatus for a lower pressure chemical vapor deposition, which providesan indirect heat transfer and electrode member and a reactor which havea function of a plasma electrode, and are disposed at a periphery of thereactor, not additionally providing the plasma electrode at the reactor.

It is another object of the present invention to provide an improvedapparatus for a lower pressure chemical vapor deposition, which providesan indirect heat transfer and electrode member or a reactor, which havea plasma electrode function, at a periphery of the reactor, notadditionally providing a plasma electrode at the reactor.

It is another object of the present invention to provide an improvedapparatus for a lower pressure chemical vapor deposition, which providesa heating jacket in which a heating medium circulates, thus conservingenergy, not using any electric heater as a reactor heating member.

It is another object of the present invention to provide an improvedapparatus for a lower pressure chemical vapor deposition, whichexpedites the dispersion of the chemical source gas by controlling theheight of the dispersion plate of the chemical source gas disposed atthe upper portion of the substrate on which the wafer is placed, so thateven thin film can be achieved.

It is another object of the present invention to provide an improvedapparatus for a lower pressure chemical vapor deposition, which providesa gas exhausting outlet for exhausting the reaction substances, gas andthe like, so that the gas in the reactor is fast exhausted to theoutside, thus enhancing the quality of thin film deposition.

It is another object of the present invention to provide an improvedapparatus for a lower pressure chemical vapor deposition, which providesthe lower surface of the wafer tightly contacting with the waferplacement section of the substrate, so that the wafer is evenly heated,thus enhancing even thickness of the thin film.

It is another object of the present invention to provide an improvedapparatus for a lower pressure chemical vapor deposition, which iscapable of correctly maintaining the loading/unloading position of thewafer.

It is another object of the present invention to provide a depositionbase, a reactor placed on the deposition base and having a reactor, asubstrate on which a wafer lifted/lowered therewithin is placed, achemical source gas introducer for introducing the chemical source gasinto the reactor, a heating member disposed at the substrate for heatingthe wafer, and a reactor heating member for heating the reactor, so thatthe heat efficiency can be enhanced by heating the wafer and the reactorat the same time.

The reactor and the chemical source gas introducer is constructed tosubstantially preheat and mix the chemical source gas.

It is another object of the present invention to provide a heatingmember between a reactor and a reactor heating member, to form a tube ora shower head constituting a reactor with a heating function material,so that the heat of the reactor heating member can heat the reactorthrough a convection or a heat transfer, thus evenly providingtemperature distribution, and thus the product having a uniformthickness can be fabricated.

It is another object of the present invention to provide a substrate anda plasma generating member having an indirect heat transfer andelectrode member with an electrode member function and an indirect heattransfer function, at the same time, so that the present invention canbe adopted to deposit and etch.

It is another object of the present invention to provide a single gasintroducing tube for introducing a chemical source gas, or to provideinner and outer gas introducing tubes for introducing at least two kindsof chemical source gases, so that various kinds of deposition films canbe fabricated.

The substrate is directed to precisely placing the substrate byproviding a position determination groove formed on the lower surface ofthe substrate and a position determination pin, mating with the positiondetermination groove, disposed at an opening/closing plate when thesubstrate is positioned at a loading/unloading position, so that theautomation of the system can be possible.

It is another object of the present invention to provide a chemicalsource gas distribution plate above the upper portion of the substrate,so that chemical source gas can be evenly provided onto the entiresurface of the wafer, thus achieving uniform deposition films.

The substrate includes a substrate body having a placement section onwhich a certain portion of the wafer except the part of the both sidescircular section thereof is placed. Here, there is further provided awafer holder having an assistant placement section on which the bothsides circular section of the wafer is placed, so that the wafer issafely placed on the substrate, thus preventing particles occurrencesand achieving better heat transfer effects of the substrate heatingmember and uniform deposition films.

To achieve the above objects, in accordance with an embodiment ofpresent invention, there is provided an apparatus for a low pressurevapor deposition, which includes a deposition base; a reactor disposedon the deposition base and having a reaction region formed therein; asubstrate lifted and lowered in the reactor and on which a wafer isplaced; a chemical source gas introducer for introducing a chemicalsource gas into the reactor; a substrate heating member disposed in thesubstrate for heating the wafer; and a reactor heating member forheating the reactor.

To achieve the above objects, in accordance with another embodiment ofthe present invention, there is provided an apparatus for a low pressurevapor deposition, which includes a deposition base; and a wafer holderhaving an assistant placement section, on which both sides circularsections of the wafer is placed, so that the wafer holder is lifted andlowered above the substrate body.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view showing a conventional low pressurechemical vapor deposition apparatus.

FIG. 2 is a cross-sectional view showing a conventional low pressurechemical vapor deposition apparatus.

FIG. 3 is a perspective view showing a substrate of an embodimentadopted in the conventional low pressure chemical vapor depositionapparatus.

FIG. 4 is a cross-sectional view showing a substrate of anotherembodiment adopted in the conventional low pressure chemical vapordeposition apparatus.

FIG. 5 is a cross-sectional view showing a low pressure chemical vapordeposition apparatus of a first embodiment according to the presentinvention.

FIG. 6 is a cross-sectional view showing a low pressure chemical vapordeposition apparatus of another embodiment according to the presentinvention.

FIG. 7 is a cross-sectional view showing a low pressure chemical vapordeposition apparatus of another embodiment according to the presentinvention.

FIG. 8 is a cross-sectional view showing a low pressure chemical vapordeposition apparatus of a second embodiment according to the presentinvention.

FIG. 9 is a cross-sectional view showing a low pressure chemical vapordeposition apparatus of a third embodiment according to the presentinvention.

FIG. 10 is a cross-sectional view of a low pressure chemical vapordeposition apparatus of another embodiment according to the presentinvention.

FIG. 11 is a cross-sectional view of FIG. 9 of a third embodimentaccording to the present invention.

FIG. 12 is a cross-sectional view of a low pressure chemical vapordeposition apparatus of another embodiment according to the presentinvention.

FIG. 13 is a cross-sectional view showing a low pressure chemical vapordeposition apparatus of a fourth embodiment according to the presentinvention.

FIG. 14 is a cross-sectional view showing a low pressure chemical vapordeposition apparatus of a fifth embodiment according to the presentinvention.

FIG. 15 is a partial enlarged cross-sectional view showing a substrateof an embodiment adopted in the present invention.

FIG. 16 is an enlarged perspective view showing a substrate of anotherembodiment adopted in the present invention.

FIG. 17 is a partial disassembled perspective view showing a substrateof FIG. 16 according to the present invention.

FIGS. 18A through 18D are views showing an operation of a substrateadopted in the present invention.

FIG. 19 is a partial perspective view showing a substrate of furtheranother embodiment adopted in the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 5 shows a low pressure chemical vapor deposition apparatus, whichincludes a deposition base 110 having a wafer inlet 111 for passing thewafer "W" therethrough and an outlet 112 for exhausting reactionsubstances therethrough, a reactor 120 mounted on an upper portion ofthe deposition base 110 and having a reaction region "R" therewithin, achemical source gas introducer 130 connected to an upper portion of thereactor 120 for introducing chemical source gas into the interior of thereactor 120, a substrate 140 movable between the loading/unloadingpositions and the deposition position for receiving the wafer "W", asubstrate heating member 150 inserted into the substrate 140 anddisposed on the substrate 140 for heating the wafer "W", and a reactorheating member 160 disposed on an upper portion of the reactor 120 forheating the reactor 120.

The deposition base 110 is mounted on a deposition facility frame (notshown) and has an opening/closing plate 113 disposed at a lower portionof the deposition base 110 for opening/closing the interior of thedeposition base 110. The opening/closing plate 113 has alifting/lowering ram 114, and the substrate 140 is fixed to an upperportion thereof, and a dust cover 115 is provided between theopening/closing plate 113 and the lifting/lowering ram 114 so as toprevent foreign matter or gas from infiltrating into the reactor 120through a certain gap of the lifting/lowering ram 114.

The lifting/lowering ram 114 is lifted/lowered by a lifting/loweringdriving member (not shown) which is of a linearly reciprocatingmechanism.

In one aspect of the present invention, the deposition base 110 and thereactor 120 are integrally formed; however, it is not limited to that.In another aspect of the present invention, they can be madeindependently from each other. In this regard, tightly engaging thedeposition base 110 and the reactor 120 is necessary.

The reactor 120 typically adopts quartz, and the upper portion thereofis closed by a sealing member 121. According to its first function, thesealing member 121 is directed to substantially blocking the interior ofthe reactor 120 from the outside or sealing the interior thereof using aquartz plate. According to its self function, the sealing member 121adopts a SiC plate so as to indirectly transfer the heat of the reactorheating member 160 into the interior of the reactor, not to directlytransfer the heat thereof thereto.

The chemical source gas introducer 130 includes an introduction tube 131connected to an upper portion of the reactor 120, a first shower head132 spaced-apart from and disposed at a lower portion of the sealingmember 121 and a second shower head 133. A gas pre-heating region "H" isdefined between the sealing member 121 and the first shower head 132 forpre-heating the chemical source gas, and a gas mixing region "M" isdefined between the first shower head 132 and the second shower head133, and a reaction region "R" is defined below the second shower head133 in which a chemical source gas is reacted.

The first shower head 132 and the second shower head 133 have showerapertures 132a and 133a, and the shower aperture 133a of the secondshower head 133 has larger diameter than that of the shower aperture132a of the first shower head 132 and the number thereof is more thanthat of the shower aperture 132a of the first shower head 132.

The first shower head 132 uses an original quartz plate, and the secondshower head 133 uses a conductive plate such as a SiC plate for co-useof the electrode so as to generate plasma.

In case of using a SiC plate as the second shower head, since thematerial thereof is non-transparent, the heat of the reactor beatingmember 160 is not directly transferred to the reaction region "R", thatis, the heat thereof is indirectly transferred thereto by conduction orconvection.

The substrate 140 is formed with a quartz plate, a carbon plate or a SiCplate and has a certain space for receiving the substrate heating member150.

A plurality of position determination grooves 141 (in drawings, only twoare seen) are formed on the lower surface of the substrate 140, and theopening/closing plate 113 includes a protruded position determinationpin 142 with respect to the position determination groove 141.

As enlarged in the circle in FIG. 5, the position determination pin 142includes a support section 142a fixed to the opening/closing plate 113integral with an insertion section 142b, which has a certain diametersmaller than that of the support section 142a, inserted into theposition determination groove 141, and an engaging jaw 142c forsupporting the lower surface of the substrate 140. The height of theengaging jaw 142c is subject to the position of the loading/unloadingposition of the substrate 140. In addition, the position determinationpin 142 is threadably engaged to the opening/closing plate 113, so thatthe height of the engaging jaw 142c can be controlled.

The substrate heating member 150 disposed in the inner upper portion ofthe substrate 140 is preferably an electric heater.

The reactor heating member 160 disposed at an upper portion of thereactor 120 is preferably an electric heater or an SiC heater.

The plasma generating member 170 is disposed between the reactor 120 andthe substrate 140 for generating plasma in the reaction region "R", anda high frequency voltage generated by a high frequency generator 171 isapplied to the second shower head 133 and the substrate 140,respectively.

Reference numeral 116 denotes a cooling water path.

The operation of the lower pressure chemical vapor deposition apparatuswill now be explained with reference to the accompanying drawings.

To begin with, the substrate 140 is lowered down to a loading/unloadingposition by lowering the lifting/lowering ram 114, and a wafer "W" isplaced on the substrate 140 through the wafer inlet 111 in a state thata certain pressure in maintained in the reactor 120 using a vacuum pump(not shown).

At this time, the insertion section 142b of the position determinationpin 142 fixed to the opening/closing plate 113 in a state that thesubstrate 140 is lowered down to the loading/unloading position isinserted into the position determination groove 141 formed on thesubstrate 140, and the lower surface of the substrate 140 is restrictedby the engaging jaw 142c of the position determination pin 142, so thatthe position of the substrate 140 is precisely determined, thuspositioning the wafer "W" on the substrate 140 using a certain membersuch as a robot hand.

In a state that the wafer "W" is placed on the substrate 140, thesubstrate 140 is lifted up to the deposition position by thelifting/lowering ram 114.

Thereafter, the wafer "W" mounted on the substrate and the reactor 120are heated at temperature of 100 through 1,100° C. by driving thesubstrate heating member 150 and the reactor heating member 160, and thechemical source gas is introduced into the reactor 120 by the chemicalsource gas introducer 130.

The chemical source gas introduced into the introduction tube 131 of thechemical source gas introducer 130 is first introduced into the gaspre-heating region "H" which is defined at the uppermost portion of thereactor 120, and is pre-heated by the reactor heating member 160, andthe chemical source gas is gushed toward the gas mixing region "M"through the shower aperture 132a of the first shower head 132.

At this time, since the shower aperture 133a of the second shower head133 has a certain diameter smaller than that of the shower aperture 132aof the first shower head 132, and the number thereof is greater thanthat of the shower aperture 132a of the first shower head 132, thechemical source gas introduced into the gas mixing region "M" issubstantially mixed therein for a certain time.

The chemical source gas introduced into the reaction space "R" throughthe shower aperture 133a of the second shower head 133 is reacted in thereactor 120 which is pre-heated to have a predetermined temperature bythe reactor heating member 160 and deposited on the wafer "W" on thesubstrate 140 as a compound thin film.

The wafer "W" mounted on the substrate 140 and the gas mixing region "M"are heated by the substrate heating member 150 and the reactor heatingmember 160, and the chemical source gas is introduced into the reactionregion "R" in a state that the gas is substantially heated, so that adesired heat effect is achieved. In addition, since the chemical sourcegas is substantially heated through the gas pre-heating region "H" andthe gas mixing region "M" which are defined by the first shower head 132and the second shower head 133 and introduced thereinto, pin holes,cracks, and step coverage do not occur in the thin film, so that it ispossible to obtain a desired better thin film.

When the deposition is completed, reaction substances or remaining gasin the reactor 120 are discharged to the outside through the outlet 112,and the substrate 140 is lowered down to the loading/unloading positionby the lifting/lowering ram 114, and the wafer "W" is unloaded throughthe wafer inlet 111 using a unloading member such as a robot hand.

In a state that the substrate 140 is lowered down to theloading/unloading position, the unloading operation can be moreprecisely executed in cooperation with the position determination groove141 of the substrate 140 and the position determination pin 142 disposedat the opening/closing plate 113.

In addition, the reaction substances or remaining gas are properlyexhausted through the outlet 112 of the deposition base 110.

Meanwhile, in this embodiment, the gas mixing region "M" and the outlet112 are connected by a remaining gas exhausting tube 117 having anopening/closing valve 118 disposed at its intermediate position.

The remaining gas exhausting tube 117 is closed during a depositionprocess by closing the opening/closing valve 118 so that the chemicalsource gas introduced into the reactor 120 is not exhausted to theoutside through the remaining gas exhausting tube 117 or the foreignmatters such as air is not introduced thereinto.

After the deposition is completed and the wafer "W" is unloaded, thereaction substances and remaining gas in the gas mixing region "M" areexhausted to the outside at a desired speed by opening theopening/closing valve 118, that is, by connecting the gas mixing region"M" and the outlet 112.

Here, since the gas mixing region "M" has a relatively small diameter,it takes some time for the remaining gas in the gas mixing region 133 tobe exhausted from the reaction region "R" to the outlet 112 through theshower aperture 133a of the second shower head 133, the thin filmdeposition may be damaged thereby. In order to resolve theabove-mentioned problems, this embodiment of the present invention isdirected to providing the remaining gas exhausting tube 117 connectingbetween the gas mixing region "M" and the outlet 112 and to opening theopening/closing valve 118 during a unloading operation, so that theremaining gas in the gas mixing region "M" is fast exhausted to theoutside, and thus it is possible to prevent the thin film deposition.

In addition, this embodiment of the present invention is directed tofabricating better thin film by expediting the reaction of the chemicalsource gas by generating plasma in the reaction region "R" by applying ahigh frequency voltage to the reactor 120 and the substrate 140.

That is, using the plasma generator 171, a high frequency voltage isapplied between the second shower head 133 formed with SiC material andthe electrode 172 disposed at the substrate 140, and plasma is generatedtherebetween, and the chemical source gas is substantially pre-heatedthrough the first shower head 132 and the second shower head 133, andthe a desired reaction can be achieved by the plasma discharge. Here, inorder to reduce fabricating cost of the product, the second shower head133 can be used as the electrode, not providing additional electrode tothe reactor 120.

FIG. 6 shows a low pressure chemical vapor deposition apparatus ofanother embodiment according to the present invention by changing theconstruction of the chemical source gas introducer 130. That is, thisembodiment is directed to providing an assistant introduction tube 134at the remaining gas exhausting tube 117 and a conversion valve 135between the remaining gas exhausting tube 117 and the assistantintroduction tube 134.

That is, in a state that the exhausting valve 118 is closed and theconversion valve 135 is opened between the assistant introduction tube131 and the gas mixing region "M" during a deposition process, thechemical source gas in introduced into the gas pre-zheating region "H"through the introduction tube 131 and introduced into the gas mixingregion "M" through the assistant introduction tube 134, so that variouskinds of thin films can be achieved by introducing various kinds ofchemical source gases into the introduction tube 131 and the assistantintroduction tube 134.

During a unloading process after the deposition is completed, theassistant introduction tube 134 connected to the gas mixing region "M"is closed by the conversion valve 135 and the remaining gas exhaustingtube 117 connected to the gas mixing region "M" is opened by theconversion valve 135, so that the remaining gas in the gas mixing region"M" is fast exhausted to the outside through the remaining gasexhausting tube 117, and thus better thin film can be achieved.

Since the operation of this embodiment is the same as the firstembodiment, it will be omitted.

FIG. 7 shows a low pressure chemical vapor deposition apparatus ofanother embodiment according to the present invention by changing theconstruction of the reactor heating member 160, which includes a jacket161 wound around the walls of the deposition base 110 and the reactor120 and another jacket 162 disposed at an upper portion of the reactor120, so that heating medias 163 and 164 are circulated within thejackets 161 and 162.

The heating medias 163 and 164 can be high temperature vapor or ethyleneglycol. When using high temperature vapor, it is necessary to provide acertain boiler so as to generate high temperature vapor, so that thesystem is costly and bulky. As a result, ethylene glycol is preferablyused in the system by heating the same using a certain heating member(not shown).

Since the remaining elements are the same as the previously describedembodiment, the descriptions will be omitted.

FIG. 8 shows a lower pressure chemical valor deposition apparatus ofanother embodiment according to the present invention, which includes adeposition base 210 having a wafer inlet 211 formed at one side thereofand an outlet 212 formed at the other side thereof for exhaustingreaction substances therethrough, a reactor 220 disposed in the upperportion of the deposition base 210 and having a reaction region "R"formed therewithin, a source gas introducer 230 connected to the upperportion of the reactor 220 for introducing the chemical source gas intothe reactor 220, a substrate 240, on which the wafer "W" is mounted,being movable within a range between a loading/unloading position and adeposition position, and a substrate heating member 250 disposed in thesubstrate 240 for heating the wafer "W". Here, this embodiment furtherincludes a reactor heating member 260 disposed at a periphery of thereactor 220 for heating the reactor 220, which is similar to the firstembodiment. However, compared with the first embodiment, theconstructions of the reactor 220 and the chemical source gas introducer230 are different therefrom. In addition, there are further provided asubstrate rotation member 243 for rotating the substrate 240 and anelectrode member 280 disposed between the reactor 220 and the reactorheating member 260.

That is, the lower aperture of the deposition base 210 can opened/closedby the opening/closing plate 213, and a lifting/lowering ram 214 ispassing through the substrate 240 and through the opening/closing plate213.

The reactor 220 includes an upper portion- and lower portion-openedhollow inner tube 221, an upper portion-closed and lower portion-openedouter tube 222, and a chemical source gas flowing path 223 formedbetween the inner and outer tubes 221 and 222.

Here, the upper portion of the inner tub 221 is lower than that of theouter tube 222, and the chemical source gas flowing path 223 and thereaction region "R" are connected to each other through the spacebetween the inner and outer tubes 221 and 222.

The chemical source gas introducer 230 includes an introducer 231connected to a lower portion of the chemical source gas flowing path223.

The lifting/lowering ram 214 for lifting/lowering the substrate 240 isrotatable by the substrate rotation member 243 and is directed toexecuting a lifting/lowering operation and a rotation operation,respectively.

The substrate heating member 250 is disposed within the inner upperportion of the substrate 240 and is directed to heating the wafer "W"which is mounted on the substrate 240.

The reactor heating member 260 winds around the upper portion and wallsof the reactor 220 and is mounted to be lower than the lower surface ofthe substrate 240.

Here, the reactor heating member 260 can be a commonly used electricheater, or as shown in FIG. 7, it can be directed to heating andcirculating ethylene glycol by providing jacket.

An indirect electric heat and electrode 280 is disposed between theupper surfaces of the reactor 220 and the reactor heating member 260.

The indirect electric heat and electrode 280 is formed with a certainmaterial having conductivity and having a characteristic that thetransmission of the heat of the reactor to the interior of the reactor220 is reduced, that is, the heat thereof is indirectly transferred tothe interior thereof. For example, it is formed of SiC material or thelike.

In drawings, reference numeral 215 denotes a flexible dust cover, and216 denotes a cooling water circulation path, 217 denotes a packingprovided between the deposition base 210 and the lower portion of theinner and outer tubes 221 and 222.

The operation of the low pressure chemical vapor deposition apparatuswill now be explained with reference to the accompanying drawings.

To begin with, the substrate 240 is lowered down to theloading/unloading position by the lifting/lowering ram 214. Thereafter,in a state that a predetermined pressure in the reactor is maintained bya vacuum pump (not shown), the wafer "W" is placed on the substrate 240through the wafer inlet 211, and the substrate 240 is lifted up to thedeposition position by the lifting/lowering ram 214.

Thereafter, the substrate heating member 250 and the reactor heatingmember 260 are driven. The chemical source gas is introduced into thereactor 220 while heating the wafer "W" placed on the substrate 240 andthe reactor at a temperature of 100 through 1,100° C.

The chemical source gas introducer 231 introduced into the chemicalsource gas introducer 230 is introduced into the reaction region "R"through the chemical source gas flowing path 223 formed between theinner and outer tubes 221 and 222 of the introduction tube 231.

The chemical source gas is substantially pre-heated through the chemicalsource gas flowing path 223, and the chemical source gas in the reactor220 is heated by a predetermined temperature by the reactor heatingmember 260 and is reacted in the reactor so as to deposit a compoundthin film on the wafer "W" mounted on the substrate 240.

Since the chemical source gas in the above-mentioned process issubstantially pre-heated through the chemical source gas flowing path223 and is introduced into the reaction region "R" of the reactor 220,so that the heat effect is increased, and thus it is possible to obtaina better thin film without pin holes, cracks, and step coverage.

In addition, since this embodiment of the present invention provides thesubstrate rotation member 243 in the lifting/lowering ram 214 forlifting/lowering the substrate 240 so as to rotate the substrate, it ispossible to obtain more even thin film by a uniform chemical source gasflowing with respect to the wafer "W".

Meanwhile, since this embodiment of the present invention provides theplasma generator 270 connected to the reactor 220 and the substrate 240for generating plasma in the reaction region "R" by applying a highfrequency voltage between the reactor 220 and the substrate 240, so thata better thin film deposition can be achieved by expediting the reactionof the chemical source gas in the reactor 220, and the inner surface ofthe reactor 120 can be etched.

That is, when the plasma generator 271 is driven, a high frequencyvoltage is applied between the indirect electric heat and electrodemember 280 formed of SiC or carbon materials and the electrode 272disposed at the substrate 240, and plasma is generated therebetween, sothat the chemical source gas in the chemical source gas flowing path 223is substantially pre-heated, and the reaction of the chemical source gasis more expedited by the plasma discharging. Here, there is no need toadditionally locate an electrode at the side of the reactor 220, thusreducing the number of parts. In addition, it is possible to use a moresimple assembly line, and fabrication of the product is not costly.

FIG. 9 shows a low pressure chemical vapor apparatus of a thirdembodiment according to the present invention. This third embodiment ofthe present invention is directed to changing the construction of thereactor 220 and the chemical source gas introducer 230. The constructionexcept the above-mentioned elements are the same as the secondembodiment, the description thereof will be omitted.

That is, in more detail, the low pressure chemical vapor apparatus ofthe third embodiment includes a reactor 220 having a lowerportion-opened and upper portion-closed tube 224, a horizontal section232a extended to the interior of the reactor 220 and passing through aside wall of the deposition base 210, and an introduction tube 232integral with a vertical section 232b which is upwardly curved from theinner side of the horizontal section 232a.

Here, the upper portion of the vertical section 232b of the introductiontube 232 is higher than that of the substrate.

This embodiment of the present invention is directed to introducing thechemical source gas into the upper portion of the reaction region "R"and has a more simple tube 224, so that the chemical source gas issubstantially heated through the vertical section 232b. As a result,this embodiment can achieve a similar result compared with the secondembodiment.

FIG. 10 shows a low pressure chemical source gas apparatus of anotherembodiment of the third embodiment according to the present invention.That is, this embodiment is directed to providing another embodiment ofthe chemical source gas introducer 230, which includes a horizontalsection 233a passing through the side wall of the deposition base, anouter introduction tube 233 having a vertical section 233b upwardlycurved from the inner end of the horizontal section 233a and a greatdiameter, and an inner introduction tube 234 having a horizontal section234a and a vertical section 234b which are inserted into the interior ofthe horizontal section 233a and the vertical section 233b of the outerintroduction tube 233, so that various kinds of chemical source gasescan be introduced into the reactor through an introduction path betweenthe inner and outer introduction tubes 234 and 233 and an induction tubeof the interior of the inner introduction tube 234, and thus variouskinds of thin film depositions can be achieved.

The upper portion of the vertical section 233b of the outer inductiontube 233 is higher than the deposition position of the substrate. Inaddition, the height of the upper portion of the vertical section of theinner induction tube 234 is preferably similar to the depositionposition of the substrate because the chemical source gas introducedthrough above two introduction paths is well mixed at a space 235between the upper portion of the vertical section of the innerintroduction tube 234 and the upper portion of the vertical section 233bof the outer introduction tube 233, so that a better thin filmdeposition can be achieved.

FIG. 11 shows a low pressure chemical vapor deposition apparatus ofanother embodiment of the third embodiment according to the presentinvention, which is directed to changing the construction of thechemical source gas introducer 230.

That is, the chemical source gas introducer 230 of this embodimentincludes an introduction tube 236 of which the upper portion thereof isextended to a predetermined portion higher than the deposition positionof the substrate and vertically passes through the opening/closing plate213 for opening/closing the lower portion of the deposition base 210.

Since the chemical source gas is substantially heated through theintroduction tube 236 by the heat of the reactor heating member 260 andis introduced into the reaction region "R", the effects similar to thesecond embodiment can be achieved.

FIG. 12 shows a lower pressure chemical vapor deposition apparatus ofanother embodiment of the third embodiment according the presentinvention, which is directed to changing the construction of thechemical source gas introducer 230.

That is, the chemical source gas introducer 230 includes an outerintroduction tube 237 of which the upper portion thereof is extended toa predetermined portion higher than the deposition position of thesubstrate, and an inner introduction tube 238 inserted into the interiorof the outer introduction tube 237 and of which the height of the upperportion thereof is similar to the deposition position of the substrate,so that various kinds of chemical source gases can be introduced throughan induction path between the inner and outer introduction tubes 238 and237 and an introduction path of the inner introduction tube 238 and canbe substantially pre-heated by the heat of the reactor heating member260, and the different chemical source gases are well mixed in a certainspace 239 defined between the inner and outer introduction tubes 238 and237 and are introduced into the reaction region "R", and thus thisembodiment can achieve the same effects as the third embodiment of thepresent invention.

FIG. 13 shows a lower pressure chemical vapor deposition apparatus of afourth embodiment according to the present invention, which includes adeposition base 310 having a wafer inlet 311 for passing through thewafer "W" and an outlet 312 for exhausting reaction substancestherethrough, a reactor 320 placed at the upper portion of thedeposition base 310 and forming a reaction region "R" therewithin, achemical source gas introducer 330 connected to the upper portion of thereactor for introducing the chemical source gas into the interior of thereactor 320, a substrate 340 movable within the reactor 320 from aloading/unloading position to a deposition position and on which thewafer "W" is mounted, a substrate heating member 350 for heating thewafer "W" mounted on the substrate 340, and a reactor heating member 360disposed at a periphery of the reactor 320 for heating the reactor 320.Here, the constructions of the reactor 320 and the chemical source gasintroducer 330 are different from the above-mentioned embodiment of thepresent invention.

That is, the reactor 320 of this embodiment mounted on the depositionbase 310 includes a lower portion-opened inner tube 321, an upperportion-closed outer tube 322 wound around the upper portion and sidewalls of the inner tube 321, and a chemical source gas flowing path 323formed between the side walls of the inner and outer tubes 321 and 322.

A predetermined gap connecting between the chemical source gas flowingpath 323 and the reaction region "R" is formed between the upper portionof the inner tube 321 and the upper surface of the outer tube 322.

In addition, the inner tube 321 is formed with a quartz tube, and theouter tube 322 is formed with a certain material such as SiC which has acharacteristic that it can indirectly heated by heat transfer orradiation heat from the reactor heating member 360. In addition, herethe outer tube 322 plays the function of the electrode of the plasmagenerator 370.

The chemical source gas introducer 330 includes an introduction tube 331connected to the lower portion of the chemical source gas flowing path323.

In drawings, reference numeral 313 denotes an opening/closing plate, 314denotes a lifting/lowering ram, 315 denotes a dust cover, 316 denotes acooling water path, 317 denotes a packing, 343 denotes a substraterotation member, 371 denotes a high frequency generator of a plasmagenerator 370, and 372 denotes an electrode disposed in the substrate340.

The deposition process of this embodiment is the same as the secondembodiment of the present invention, except that the material of theouter tube 322 of the reactor 320 has two functions of an indirect heattransfer function and an electrode function.

FIG. 14 shows a low pressure chemical vapor deposition apparatus of afifth embodiment according to the present invention, which includes anupper portion-opened and lower portion-opened deposition base 410 havinga wafer inlet 411 for passing through the wafer "W" therethrough and anoutlet 412 for exhausting reaction substances therethrough, a reactor420 mounted on the deposition base 410 and having a reaction region "R"formed therein, a chemical source gas introducer 430 connected to theupper portion of the reactor 420 for introducing the chemical source gasinto the interior of the reactor 420, a substrate 440 movable within thereactor 420 from a loading/unloading position to a deposition position,a substrate heating member 450 disposed in the substrate 440 for heatingthe wafer "W", and a reactor heating member 460 disposed at a peripheryof the reactor 420 for heating the reactor. The construction of thisembodiment is similar to the fourth embodiment except the constructionsof the reactor 420 and the chemical source gas introducer 430.

That is, the reactor 420 includes a lower portion-opened and upperportion-closed tube 421, which is formed with SiC. Here the SiC tube 421plays an indirect heat transfer function and a plasma generatingfunction including its basic function of providing a reaction region"R".

In addition, the chemical source gas introducer 430 includes anintroduction tube 431 vertically passing through the opening/closingplate 413 of the deposition base 410 and having the upper portionextended to a predetermined portion higher than the substrate.

In FIG. 14, reference numeral 413 denotes an opening/closing plate, 414denotes a lifting/lowering ram, 415 denotes a dust cover, 416 denotes acooling water path, 417 denotes a packing, 413 denotes a substraterotation member, 471 denotes a high frequency generator of the plasmagenerator 470, and 472 denotes an electrode of the substrate 440.

The deposition process including an introduction process of introducingthe chemical source gas of this embodiment is the same as the previousembodiment except that the reaction path 420 is formed with single tube421. That is, this embodiment includes the single tube 421 having anindirect heat transfer and the electrode function. In more detail, theindirect heat transfer and electrode member is not necessary.

FIG. 15 shows a substrate of another embodiment according to the presentinvention. That is, the substrate 540 includes a chemical source gasdispersion plate 544 for evenly introducing the chemical source gas overthe entire surface of the wafer "W" mounted on the substrate 540.

The substrate 540 and the dispersion plate 540 are engaged by a gapcontrol member 545 for controlling the gap therebetween.

The gap control member 545 includes threaded bars 547 and 548 connectedto the substrate 540 and the dispersion plate 544 and a turn buckle-typecontrol knob 546 engaged to the threaded bars 547 and 548. The threadedbars 547 and 548 includes each three threaded bars and is disposed so asto prevent any interference from the wafer "W" which loaded/unloadedthrough the wafer inlet 511.

The substrate 540 is directed to evenly introducing the chemical sourcegas over the entire surface of the wafer "W" by preventing the chemicalsource gas from being directly introduced onto the surface of the wafer"W" in a process that the chemical source gas is introduced into thereaction region "R" and from unevenly and partially introducing onto thesurface of the wafer "W" by allowing the chemical source gas to coverthe surface of the wafer "W" through the gap formed between the wafer"W" on the substrate 540 and the dispersion plate 544, so that eventhickness of a thin film can be achieved.

In addition, a desired thin film can be achieved by controlling the gapbetween the upper surface of the substrate 540 and the dispersion plate544 in accordance with the conditions of the chemical source gas and thethin film.

The above-mentioned construction is not limited to its range of use. Ifpossible, the construction can be used for any embodiments having aconstruction for controlling the gap therebetween.

FIG. 16 shows a substrate of another embodiment adopted in the lowpressure chemical vapor deposition apparatus of the present invention,which is directed to achieving a desired loading/unloading operationusing a robot hand "A" and receiving the entire surface of the wafer"W".

That is, the substrate 600 includes a substrate body 610 having aplacement section 611 for substantially receiving the wafer "W" exceptthe part of the circular portion C1 thereof and a wafer holder 620having an assistant placement section 625 for receiving the remainingcircular part of the wafer "W".

A circular protrusion 615a contacting with the outer circumferentialsurface of the circular section C1 of the wafer "W" are formed on thecircular section 615 of the placement section 611.

The length of the straight line section 613 is the same as the length ofthe flat zone "F" of the wafer "W".

The circular protrusions 615a and 616a are protruded by preferably about0.8 mm which is thickness of the wafer "W".

The wafer holder 620 is formed to be U-shaped by a connection circularsection 624 formed between the both sides straight line section 623 andthe straight line sections 622 and 625.

The outer diameter of the wafer holder 620 is the same as the outerdiameter of the substrate body 610, and the width of the cut-away grooveis wider than that of the robot hand "A".

An assistant placement section 625 is formed at the both sides straightline section 625, on which the both sides circular section C1 of thewafer "W" is mounted.

A circular protrusion, in which the outer circumferential surface of theboth sides circular section C1 contacts with the inner surface thereof,is formed at a periphery of the assistant placement section 625a. Thecircular protrusion is protruded by about 0.8 mm which is similar to thethickness of the wafer "W".

In addition, the holder lifting/lowering bar 630 is provided so as tolifting/lowering the wafer holder 620.

The holder lifting/lowering bar 630 includes a plurality of connectionbars 631 (preferably three bars) of which the upper end is connected tothe outer end of the wafer holder 620, and a lifting/lowering connectionbar 534 for fixing the lower ends of the connection bars 631, so thatthe lifting/lowering connection bars 634 are lifted/lowered by alifting/lowering member (not shown).

A plurality of connection plates 632 and 635, which has the same numberas the connection bars), are protruded from the outer end of the waferholder 620, so that the wafer holder 620 and the lifting/lowering bars634 are integrally connected by fixing the higher and lower ends of theconnection bars 631 to the connection plates 632 and 635 using fixingscrews 633 and 636.

Here, since the connection bars 631 are disposed at the rear portion andat both sides of the wafer holder 620, there is not any interferencebetween the connection bars 631 and the wafer "W" while the wafer "W" isloaded or unloaded.

A ram aperture 637, through which the lifting/lowering ram passesthrough for lifting/lowering the substrate, is formed at the centralportion of the lifting/lowering connection bar 634, so that there is notany interference between the lifting/lowering ram and the holderlifting/lowering bar 630.

A screw aperture 638 for engaging the lifting/lowering drive member isformed at a periphery of the ram aperture 637 of the lifting/loweringconnection bar 634.

The lifting/lowering drive member is not limited to its range of use ofhydrogen cylinder, pneumatic cylinder, step motor, or linearlylifting/lowering drive device using motorized-screw.

The operation of loading/unloading the wafer "W" on/from the substrate600 of this embodiment according to the present invention will now beexplained.

To begin with, as shown in FIGS. 16 through 18A through 18D, the wafer"W" is moved immediately above the wafer holder 620 by lifting theholder lifting/lowering bars 630 by the lifting/lowering drive member ina state that the lower surface of the wafer holder 620 is spaced apartfrom the upper surface of the substrate 610.

Referring to FIG. 18B, the flat zone "F" of the wafer "W" is mated withthe straight line section of the substrate straight section 613, and theboth sides circular section C1 of the wafer "W" is mated with the bothsides assistant placement section 625a of the wafer holder 620, and asshown in FIG. 18C, the robot hand "A" is lowered and places the wafer"W" on the assistant placement section 625a of the wafer holder 620.

At this time, since the width of the robot hand "A" is narrower than theinner width of the cut-away groove 621 of the wafer holder 620, there isnot any interference between the robot hand "A" and the wafer holder620.

The wafer "W" on the wafer holder 620 is placed on the assistantplacement section 625a, and the outer ends of the both sides circularsection C1 comes into contact with the circular protrusions 625a.

Next, when the robot hand "A" comes off from the wafer holder 620, onlythe wafer "W" is placed on the holder 620.

When the robot hand "A" comes off from the wafer holder 620, the waferholder 620 is lowered in accordance with a lowering of the holderlifting/lowering bar 630 which is lowered by the lifting/lowering drivemember, so that as shown in FIG. 18D, the wafer is placed on theplacement section 611.

When using the above-mentioned substrate 600, the heat from thesubstrate heating member disposed in the substrate body 610 is directlytransferred to the region of the placement surface 612 of the placementsection 611, and the heat therefrom is transferred to the region of theassistant placement section 625a of the wafer holder 620 through thewafer holder 620, so that the heat is evenly transferred to the entiresurface of the wafer "W".

Therefore, since the wafer "W" is tightly placed on the substrate 600,the deposition is evenly conducted over the entire surface of the wafer"W", so that better thin film without particle and cracks can beachieved, and a desired uniformity of the thin film can be alsoachieved, and the heat loss can be advantageously prevented.

In addition, since a thin lifting/lowering pin is not used as theconventional art, it is possible to prevent breakages of parts, and themaintenance is easier compared with the prior art.

Moreover, in a state that the outer end of the circular section C1 ofthe wafer "W" contact with the placement section and the inner surfaceof the circular protrusions 615a and 625a formed on the wafer holder620, since the wafer "W" is placed, the heat efficiency can beincreased.

FIG. 17 shows a substrate of another embodiment according to the presentinvention, which is directed to controlling heat transfer efficiencywith respect to the wafer "W" in accordance with a kind of thin film tobe deposited by providing a wafer holder 602 having an outer diametersmaller than the outer diameter of the substrate body 610.

In addition, the length of the connection plate 632 connected with theconnection bar 631 is longer than that in the previous embodiment sincethe outer diameter of the wafer holder 620 is smaller than that of thesubstrate body 610.

Since the remaining constructions are the same as the embodiment of FIG.16 trough FIGS. 18A through 18D, the description with respect theretowill be omitted.

The above-mentioned aspect can be adopted to all the embodiments of thepresent invention.

Although the preferred embodiments of the present invention have beendisclosed for illustrative purposes, those skilled in the art willappreciate that various modifications, additions and substitutions arepossible, without departing from the scope and spirit of the inventionas described in the accompanying claims.

What is claimed is:
 1. An apparatus for a low pressure chemical vapordeposition, comprising:a supporting base; a reactor disposed on saidsupporting base, said reactor including an upper portion-opened andlower portion-opened single tube; a sealing member for sealing an upperaperture of said upper portion-opened and lower portion-opened singletube; a substrate being movable between a loading/unloading position anda deposition position within said reactor for receiving a wafer thereon;a chemical source gas introducer for introducing a chemical source gasinto the reactor; substrate heating means disposed in said substrate forheating said wafer; and reactor heating means for heating the reactor.2. The apparatus of claim 1, wherein said reactor heating means isdisposed at the upper portion of the reactor in a state that the reactorheating means is spaced apart from the reactor.
 3. The apparatus ofclaims 1, wherein said reactor heating means is disposed at an upperportion of the reactor and an inner wall thereof, in a state that thereactor heating means is spaced apart from the upper portion of thereactor and the inner wall thereof.
 4. The apparatus of claim 1, whereinsaid sealing member is formed with a material having a heat transferfunction.
 5. The apparatus of claim 1, wherein said chemical source gasintroducer includes:an introduction tube connected to an upper portionof a wall of the reactor; and a first shower head and a second showerhead which define a gas pre-heating region, a gas mixing region, and areaction region.
 6. The apparatus of claim 5, wherein both of said firstshower head and said second shower head include a plurality of showerapertures, said shower apertures of the second shower head being acertain size smaller than that of the first shower head, and the numberof the shower apertures of the second shower head being greater thanthat of the first shower head.
 7. The apparatus of claim 5, wherein anoutlet is connected to said gas mixing region by a remaining gasexhausting tube, said remaining gas exhausting tube having a conversionvalve disposed at a predetermined position.
 8. The apparatus of claim 7,wherein said remaining gas exhausting tube includes an assistantintroduction tube connected thereto and a connection section having aconversion valve.
 9. The apparatus of claim 5, wherein said secondshower head is formed with a certain material having a heat transferfunction and an electrode function.
 10. The apparatus of claim 9,wherein said apparatus includes an electrode disposed at the substrateand plasma generating means having a high frequency generator connectedto the second shower head.